// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

const TUint32 KRBMask = 0x00ff00ff;

const TUint32 KAGMask = 0xff00ff00;

const TUint32 KGMask  = 0x0000ff00;

const TUint16 NormalisationTable[256] = {

    0,65280,32640,21760,16320,13056,10880,9326,8160,7254,6528,

    5935,5440,5022,4663,4352,4080,3840,3627,3436,3264,

    3109,2968,2839,2720,2612,2511,2418,2332,2252,2176,

    2106,2040,1979,1920,1866,1814,1765,1718,1674,1632,

    1593,1555,1519,1484,1451,1420,1389,1360,1333,1306,

    1280,1256,1232,1209,1187,1166,1146,1126,1107,1088,

    1071,1053,1037,1020,1005,990,975,960,947,933,

    920,907,895,883,871,859,848,837,827,816,

    806,797,787,778,768,760,751,742,734,726,

    718,710,702,695,688,680,673,667,660,653,

    647,640,634,628,622,616,611,605,599,594,

    589,583,578,573,568,563,558,554,549,544,

    540,536,531,527,523,519,515,510,507,503,

    499,495,491,488,484,480,477,474,470,467,

    463,460,457,454,451,448,445,442,439,436,

    433,430,427,424,422,419,416,414,411,408,

    406,403,401,399,396,394,391,389,387,384,

    382,380,378,376,374,371,369,367,365,363,

    361,359,357,355,353,351,350,348,346,344,

    342,340,339,337,335,334,332,330,329,327,

    325,324,322,320,319,317,316,314,313,311,

    310,308,307,306,304,303,301,300,299,297,

    296,295,293,292,291,289,288,287,286,284,

    283,282,281,279,278,277,276,275,274,272,

    271,270,269,268,267,266,265,264,263,262,

    261,260,259,258,256,

};

//Algoriths for Premultiplied alpha screenmode/pixel format.

/**

Blend A over B. From Porter & Duff:

C = CaFa+CbFb, where Ca = aSrcPixel, Cb = aDest_io, Fa = 1, Fb=(1-Alpha(a))

C = Ca+Cb(1-Alpha(a))

@param aDestPixel			Destination pixel.

@param aSrcPixel		Source pixel.

@param aMaskingFactor	Alpha channel of aSrcPixel.

*/

inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor)

	{

	TUint32 src_c = aSrcPixel & KRBMask;

	TUint32 dst_c = aDestPixel  & KRBMask;

	const TUint32 mask = 0x0100 - aMaskingFactor;

	dst_c = (src_c +  ((mask * dst_c)>>8)) & KRBMask;

	src_c = (aSrcPixel & KAGMask)>>8;

	TUint32 dst_ag = (aDestPixel & KAGMask)>>8;

	dst_c |= ((src_c +  ((mask * dst_ag)>>8)) & KRBMask)<<8;

	return dst_c;

	}

inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask)

	{

	if(aMask)

		{

		if(aMask == 0xff) // opaque, so unchanged

			{

			return aSrcPixel;

			}

		else

			{

			return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask);

			}

		}

	 else // completely transparent

		{

		return aDestPixel;

 		}

	}

inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel)

	{

	TUint8 mask = (TUint8)(aSrcPixel >> 24);

	return PMAPixelBlend(aDestPixel, aSrcPixel, mask);

	}

inline TUint32 NonPMA2PMAPixel(TUint32 aPixel)

	{

	TUint8 tA = (TUint8)(aPixel >> 24);

	if (tA==0)

		{ 

		return 0;

		}

	if (tA==0xff) 

		{

		return aPixel;

		}

	// Use a bias value of 128 rather than 255, but also add 1/256 of the numerator 

	// before dividing the sum by 256.

	TUint32 tap1=tA+1;

	TUint32 scaledRB = (aPixel & KRBMask) * tap1;

	TUint32 scaledG = (aPixel & KGMask ) * tap1;

	return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask);

	}

inline TUint32 PMA2NonPMAPixel(TUint32 aPixel)

	{

	TUint8 alpha = (TUint8)(aPixel >> 24);

	if (alpha==0)

		{ 

		return 0;

		}

	if (alpha==0xff) 

		{

		return aPixel;

		}

	TUint16 norm = NormalisationTable[alpha];

	TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask;

	TUint32 norm_g =  (((aPixel & KGMask ) * norm) >> 8) & KGMask;

	return ((aPixel & 0xff000000) | norm_rb | norm_g);

	}